The invention relates to a method for checking the driftability of metallic tubes.
In various customer specifications/regulations a so-called “drifting” is required before tubes are delivered, wherein a cylindrical body with a defined length is guided through the tube. The test of body is hereby pulled, pushed or shot through the tube. This test is important, for example, for drill pipes used in oil exploration, because a drill head having a defined diameter must be guided to the drilling site.
Drifting of pipes ensures that a predetermined inside diameter in combination with a minimum straightness is maintained.
If the drift body gets stuck in the pipe, then a decision has to be made if reworking, e.g., by grinding, should be performed, or if the pipe can be assigned to another job or if the pipe may even have to be scrapped.
These drift tests are, on one hand, very costly and time-consuming and have, on the other hand, the disadvantage that they must be performed outside the typical pipe production flow.
The test results are therefore available only at a later time in the production process so that any required changes in the manufacturing parameters can only be performed very late. This causes increased scrap or more rework, or both.
Moreover, drift bodies may disadvantageously get stuck in the pipe during drift tests, necessitating a shutdown of the test facility and hence costly downtime.